Temporally defined induction of c-fos in the rat pineal.

In the rat pineal gland c-fos is transiently and markedly induced after the onset of darkness. The induction is abolished following removal of the superior cervical ganglion and reproduced in ganglionectomized animals by treatment with the adrenergic agonist isoproterenol. These findings show for the first time that induction of c-fos forms an integral part of physiological changes in cellular activity. Expression of the c-fos gene may be functionally linked to the nocturnal changes in pineal indole metabolism.